Project Files of 12V Solar Panel Library for Proteus V1.0 (Arduino, INA219)

12V SOLAR PANEL LIBRARY FOR PROTEUS - V1.0 (a 12 V monocrystalline solar
panel, 36 cells: its I-V curve with the light, the heat, the shade and the
bypass diodes)
Designed by The Engineering Projects
www.TheEngineeringProjects.com

IMPORTANT LINKS
Article (read it first - pictures, step by step, every feature explained):
  https://www.theengineeringprojects.com/2026/11/12v-solar-panel-library-for-proteus-v1-0.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/motor-driver-proteus-library
The demo runs on our Arduino UNO V4.0 (included) - working LEDs, RESET and a
built-in serial monitor - its own article:
  https://www.theengineeringprojects.com/2026/10/arduino-uno-library-for-proteus-v40.html
The demo measures the panel with our INA219 Current Sensor and its DC
electronic load - a SEPARATE library, not in this package: download and
install it first - its own article:
  https://www.theengineeringprojects.com/2026/10/ina219-current-sensor-library-for-proteus-v1-0.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
12V-Solar-Panel-TEP-v1.0/
|-- Proteus Library Files/
|   |-- ArduinoV4TEP.LIB                              201.9 KB   TEP Arduino boards V4.0 (UNO) -> LIBRARY
|   |-- TEPSOLAR.LIB                                   40.5 KB   the library -> LIBRARY folder
|-- Proteus Model Files/
|   |-- TEPARDUINO.DLL                                883.5 KB   the Arduino board model -> MODELS folder
|   |-- TEPSOLAR.DLL                                  311.5 KB   the model -> MODELS folder
|-- Proteus Simulation/
|   |-- 12V-Solar-Panel-INA219-ArduinoUnoV4.pdsprj     27.0 KB   the demo project
|   |-- Solar_Demo.hex                                 24.7 KB   the demo firmware
|   |-- TEPARDUINO.DLL                                883.5 KB   copy of the board model
|   |-- TEPSOLAR.DLL                                  311.5 KB   copy of the model
|-- Arduino Code/
|   |-- Solar_Demo/Solar_Demo.ino                       4.4 KB   the demo sketch (source of the .hex)
|-- README.txt                                        ~18.5 KB   this file
Total: 2.64 MB (unzipped). The C++ source code of the models is not included.

WHAT IS IT?
A simulation model of the "12 V" solar panel - the aluminium-framed
monocrystalline panel of 10 to 100 W that charges 12 V batteries in garden
lights, gate openers, boats, caravans, weather stations and off-grid Arduino
projects. Our own model:
  * 36 cells in series, as two strings of 18, each string with a bypass
    diode in the junction box. Each cell follows the single-diode model; the
    panel is fitted so it gives exactly its rated watts at the standard test
    conditions (STC: 1000 W/m2, cells at 25 C): Voc 21.6 V, about 17.6 V at
    the maximum power point (MPP), Isc 61 mA per rated watt (1.22 A for 20
    W).
  * Its current depends on the voltage the circuit holds it at: the I-V
    curve. Ask for less current and the voltage rises towards Voc; ask for
    more than the light makes (Isc) and the voltage collapses. Only one
    point gives the most power - the MPP - and it moves with the light.
  * The light (property IRRADIANCE and the pop-up's chips Night, Cloudy,
    Bright, Full sun): the current follows it; the voltage only falls a
    little in weak light.
  * The heat (property AMBIENT): in the sun the cells warm towards the air
    + 31 C (NOCT 45 C) over about 3 minutes; Voc falls 0.33 % a degree, Isc
    rises 0.05 % a degree, the power falls about 0.43 % a degree.
  * The shade (pop-up chips): a leaf on one cell starves its whole string of
    18; when the load wants more, that string's bypass diode carries the
    current (about -0.4 V) and the P-V curve gets two peaks. A pole's shadow
    across both strings cuts the whole panel down - no bypass diode helps.
  * At night, or with a battery straight on it, current flows back INTO the
    panel; a source the wrong way round drives its bypass diodes.
  * The cells' capacitance (1 uF on a 20 W panel) is in the circuit too, so
    a load that wants more than the panel makes collapses it smoothly.
  * The watch: AT THE MPP, OUTPUT (with the share of the best this light
    gives), OPEN CIRCUIT, COLLAPSED, BYPASS DIODE ON, NIGHT, REVERSE
    CURRENT, REVERSED, HOT, the light and the shade; the energy, and how much
    of what the light offered the load took.
The symbol is just the panel: the silver aluminium frame, the glass over 36
dark-blue pseudo-square cells (9 x 4) on a white backsheet with their busbars,
the red and black cables with their MC4 connectors (the pins). At Run the
cells' glare follows the light, they go dark at night, and a leaf or a pole's
shadow lies on them. On the frame's bottom rail: the value line (the rating
when stopped; the watts, volts, amps and the state at Run), the OUT LED (green
while it delivers power) and the OPEN PANEL button. The value line, the LED,
the button and the shade on the cells are TEP additions; a real panel has
none of them. The sun, the clouds and the night are drawn in the pop-up.

ONE DEVICE (search "solar" in Pick Devices):
  SOLARPANELTEP    "12V Solar Panel V1.0"   (category Electromechanical >
                   Renewable Energy), model TEPSOLAR.DLL
  The pop-up panel "TEP 12V Solar Panel" opens at Run (and with OPEN PANEL on
  the frame) - the look of the TEP Serial Monitor. Tabs Panel, Graphs, Event
  log and Check; gear and ? icons for Settings and Help; the palette icon
  switches the theme:
    Panel      the light chips (Night, Cloudy, Bright, Full sun) and the shade
               chips (No shade, Leaf, Shadow); the state in big letters; the
               I-V and P-V curves for this light with the MPP (green) and the
               panel's operating point (orange); the live values (the power,
               the state, the volts, the current, the best (MPP), the share
               the load takes, the light, the cells); the sky and the panel
               (the sun, clouds or the moon, the leaf or the shadow); the
               last 10 s: the power against the most this light gives.
    Graphs     the power against the best, the volts and the current over the
               last 10, 30 or 60 s. Live / Freeze.
    Event log  AT THE MPP, OUTPUT, COLLAPSED, BYPASS DIODE ON, the light, the
               shade, the warnings; filters All / Output / Warnings, Pause,
               Clear
    Check      Good for: a panel that gives less than its label, a voltage
               that collapses, a battery that goes flat overnight - the light,
               the operating point, the load, the shade, the cells, the
               polarity, the energy, with tips
    Settings   theme, text size, open at Run, window size
    Help       report a bug, suggest a feature, article, updates, donate,
               forum; Copy diagnostics for a bug report

TEST STATUS
V1.0: verified in Proteus 8.5 on 30 Oct 2026 (the demo project as shipped: an
A3 sheet, an Arduino UNO V4.0 with its built-in monitor, our INA219 - its
pop-up version - and its DC load at 1.1 A, from their own library, the 20 W
panel in full sun; all pop-ups open). What the run showed:
  * Full sun, 1.1 A: "AT THE MPP - 18.06 V x 1.100 A = 19.86 W (1000 W/m2,
    cells 25 C): the most this light gives"; the ON LEDs lit (UNO, INA219,
    the panel's OUT); the INA219's pop-up "MEASURING - BUS 17.936 V, SHUNT
    110.02 mV, CURRENT 1.100 A, POWER 19.732 W".
  * The load's MOTOR preset (0.8 A): "OUTPUT 19.70 V x 0.800 A = 15.77 W - 79
    % of the 20.0 W it could give at 17.6 V".
  * LAMP (1.5 A): "COLLAPSED - the load wants more than the 1.22 A this light
    makes: 0.53 V x 1.220 A = 0.65 W".
  * 0.8 A and the Leaf chip: "A LEAF on one cell (set on the panel): its
    string makes 20 % - peaks 9.5 W at 8.4 V and 4.2 W at 18.3 V", "BYPASS
    DIODE ON - a shaded string is bypassed: 9.44 V x 0.800 A = 7.55 W (the
    best: 9.5 W at 8.4 V)".
  * The Shadow chip: "the best now 5.6 W at 16.7 V", "COLLAPSED - the load
    wants more than the 0.37 A this light makes: 0.27 V x 0.366 A = 0.10 W".
  * No shade, Cloudy: "the most it can give now is 3.6 W at 16.3 V"; at 0.25
    A "COLLAPSED - the load wants more than the 0.24 A this light makes: 0.51
    V x 0.244 A = 0.13 W"; at 0.05 A "OUTPUT 19.21 V x 0.050 A = 0.96 W - 27 %
    of the 3.6 W it could give at 16.3 V".
  * Bright, 0.25 A: "OUTPUT 20.10 V x 0.250 A = 5.02 W - 43 % of the 11.6 W it
    could give at 17.1 V". Night: "NIGHT - no light: 0.00 V, the panel makes
    nothing".
  * Full sun, 0.8 A at the end: "OUTPUT 19.47 V x 0.800 A = 15.58 W - 79 % of
    the 19.7 W it could give at 17.3 V" (the cells at 29 C); the monitor's
    "best": "Best so far: 19.87 W at 18.06 V, 1.100 A".
  Plus automatic checks on a PC, 0 failed: 15 on the panel (10 / 20 / 50 /
  100 W at STC: Voc 21.60 V, Isc 61 mA a watt, the rated watts at 17.60 V;
  200 W/m2: 3.66 W; cells at 56 C: 12.8 % less; 6.2 mA back in from a 12.6 V
  battery at night; a leaf: two peaks, 9.57 W at 8.45 V and 4.23 W at 18.40
  V, the bypass diode on; a pole's shadow: 5.67 W; reversed: the bypass
  diodes; the stamp with a resistor and the DC load at 0.8, 1.1 and 1.5 A)
  and 4 on the pop-up (every page painted).

INSTALLATION (about 2 minutes)
1. Close Proteus. Extract the WHOLE ZIP to a normal folder (e.g. Desktop).
2. Copy everything in "Proteus Library Files" (TEPSOLAR.LIB and our Arduino
   library V4.0, ArduinoV4TEP.LIB) to the LIBRARY folder of Proteus, for
   example:
     C:\Program Files (x86)\Labcenter Electronics\Proteus 8 Professional\LIBRARY
   (on some PCs: C:\ProgramData\Labcenter Electronics\Proteus 8 Professional\
   LIBRARY - use the folder that already holds Proteus's own .LIB files).
3. Copy TEPSOLAR.DLL and TEPARDUINO.DLL from "Proteus Model Files" to the
   MODELS folder (...\Proteus 8 Professional\MODELS). The demo's INA219 and
   DC load are NOT in this package: install our INA219 Current Sensor
   library the same way (its own ZIP - see IMPORTANT LINKS): TEPINA219.LIB
   and TEPINA219.DLL.
4. Delete TEPSOLAR.IDX from the LIBRARY folder if it is there.
5. Start Proteus. In Pick Devices (P) search "solar".

RUN THE DEMO
"Proteus Simulation\12V-Solar-Panel-INA219-ArduinoUnoV4.pdsprj" - keep the
.hex file and the DLLs beside the project (with the INA219 library
installed).
  ARD1: Arduino UNO V4.0 running Solar_Demo.hex, its serial monitor built in
        (window "TEP Arduino UNO - ARD1").
  U1:   our INA219 (Advance: its pop-up), SDA / SCL on the UNO's A4 / A5 by
        labels; VIN+ on the PV+ net, VIN- straight into the load.
  LD1:  the INA219 library's TEP DC electronic load, 1.1 A (the MPP of a
        20 W panel in full sun); - to ground.
  PV1:  the panel (WATTS=20, IRRADIANCE=1000, AMBIENT=25): + on the PV+ net,
        - to ground.
  1. Press Run. The monitor and the two pop-ups open (move them aside). In
     full sun at 1.1 A the panel sits at its maximum power point.
  2. On the INA219's pop-up: the load presets (UNO 50 mA, SERVO 250 mA,
     MOTOR 800 mA, LAMP 1.5 A ...) - watch the operating point move on the
     panel's curves.
  3. On the panel's pop-up: Night, Cloudy, Bright, Full sun; No shade,
     Leaf, Shadow.
  4. Type in the monitor and press Send: best, reset, rate 500, help.
  5. Double-click PV1: WATTS (10 / 20 / 50 / 100), IRRADIANCE (W/m2),
     AMBIENT (C).

WIRING (the same idea in a project)
  The panel charges a battery through a charge controller (PWM or MPPT),
  never straight: a battery on a bare panel runs back into it at night, and
  the panel's 21 V open-circuit voltage overcharges it in the sun. To
  measure the panel with an Arduino, put a current sensor (INA219, INA226,
  ACS712) in its + line and read the volts with a divider (21.6 V is too
  much for an analog pin: 1:5 is a safe ratio).
In the sketch (Wire only): read the INA219's shunt register (10 uV a step)
and bus register (4 mV a step, bits 15..3):
  float amps  = readReg(0x01) * 0.00001 / 0.1;      // the shunt volts / 0.1 ohm
  float volts = ((uint16_t)readReg(0x02) >> 3) * 0.004 + amps * 0.1;
The demo reads the bus before and after the shunt and only trusts a reading
when the two agree (the panel did not change in between), and writes the
calibration (4096 for the 0.1 ohm shunt) so the INA219's own Current and
Power registers work too.
REAL HARDWARE:
 * The label's watts are for 1000 W/m2 and cells at 25 C: expect 70 - 85 %
   of it on a sunny day (warm cells, the angle, dust).
 * Point it at the sun: a 30 degree tilt facing the equator is a good
   start; keep it out of shade - a leaf on one cell costs half the panel.
 * Use a charge controller with a battery; fit a blocking diode if you
   connect a battery without one.
 * Mind the polarity of MC4 connectors: a reversed battery drives large
   currents through the bypass diodes.

THE DEMO SKETCH ON THE SERIAL MONITOR (Solar_Demo V1.0, 9600 baud)
  best      the best point so far          reset     forget it
  rate N    report every N ms (200 - 5000) help      the list
EXPECTED MONITOR OUTPUT
  12V Solar Panel demo - The Engineering Projects
  The panel feeds the DC load through the INA219 (0x40 on A4 / A5, 0.1 ohm shunt). Set the load on its pop-up.
  Commands: best | reset | rate 1000 | help
  (then a line every second: PV, volts, amps, watts)

PROPERTIES (double-click the part > Edit Properties)
  WATTS       the panel: 10, 20, 50 or 100 (W at STC); default 20
  IRRADIANCE  the light at the start, W/m2 (0 - 1200); default 1000
  AMBIENT     the air, C (-20 - 50); default 25 - the cells start at it
Every run starts again from the properties.

TROUBLESHOOTING
* COLLAPSED: the load wants more current than the light makes - a smaller
  load, more light, or a bigger panel.
* OPEN CIRCUIT: nothing takes the power - check the load's wiring.
* BYPASS DIODE ON: a shaded string is bypassed - remove the shade.
* REVERSE CURRENT: something pushes current into the panel (a battery at
  night) - fit a blocking diode or use a charge controller.
* REVERSED: a source is connected the wrong way round - check + and -.
* The part is not simulated: TEPSOLAR.DLL is missing from MODELS and from the
  project folder. No INA219 or no DC load: install our INA219 library
  (TEPINA219.LIB / .DLL). No UNO / no monitor window: TEPARDUINO.DLL, or click
  the UNO's USB port.
* The pop-up does not appear: click OPEN PANEL on the frame, or turn "Open the
  panel at Run" on its Settings page back on.

BUG REPORTS AND FEATURE REQUESTS
Please post them in our forum with a screenshot, the Serial Monitor text, the
simulation log and the pop-up's Copy diagnostics text:
  https://www.theengineeringprojects.com/forum/category/motor-driver-proteus-library

SUPPORT US
This library is free. If it saves you time, please support our work:
  https://www.theengineeringprojects.com/donate

LICENCES AND THIRD-PARTY NOTES
* The panel model (TEPSOLAR.DLL), the symbol and artwork and the Arduino
  Library V4.0 (ArduinoV4TEP.LIB / TEPARDUINO.DLL) are made by The Engineering
  Projects. The model is an independent implementation of the standard
  single-diode solar cell model, fitted to the typical data of 12 V (36-cell)
  monocrystalline panels. The models use only standard Windows libraries; no
  Visual C++ redistributable is needed. The C++ source code is not included.
  The demo's INA219 and DC load, our INA219 Current Sensor library
  (TEPINA219.LIB / TEPINA219.DLL), are a separate download.
* The demo's .hex is built from the demo sketch and the Arduino AVR core 1.8.6
  (with its Wire library), which includes LGPL-licensed code; its source code
  is available at https://github.com/arduino/ArduinoCore-avr/tree/1.8.6
* Proteus is a product of Labcenter Electronics and is not included. Arduino is
  a trademark of Arduino SA. This library is not made or endorsed by any panel
  maker, Arduino or Labcenter.

REBUILDING THE FIRMWARE (OPTIONAL)
The HEX file is supplied; Arduino IDE is not needed to run the demo. To edit
the sketch, open Arduino Code\Solar_Demo\Solar_Demo.ino, select Arduino Uno
and use Sketch > Export Compiled Binary. The sketch needs 8,990 bytes of flash
(28 % of the UNO) and 496 bytes of RAM.

MODEL SCOPE AND LIMITS
Modelled: the cells (the single-diode model: the photocurrent, the diode, the
series and the shunt resistance), the two strings and their bypass diodes,
the light, the cells' temperature and its coefficients, the warm-up, the
shade on a cell or across the strings, the cells' capacitance, the current
flowing back in, a reversed connection, the energy and the watch's states and
warnings.
How it runs: at each Newton step the panel is in the circuit as the tangent
of its I-V curve at that step's voltage, plus its capacitance in transient;
the analog step is held to 0.1 ms after a change and grows to 1 ms when the
panel is steady, with smaller steps while its voltage swings.
Not modelled: the angle of the sun (set the light instead), spectral effects,
cell cracks and hot spots, the slow loss of power over the years, partial
shading of a single cell's area (a shaded cell is a whole cell at a share of
the light).

VERSION
TEP 12V Solar Panel library V1.0 (Oct 2026). Device SOLARPANELTEP
(TEPSOLAR.LIB / TEPSOLAR.DLL). Demo sketch Solar_Demo V1.0. Demo sensor and
load: INA219ADVTEP and DCLOADTEP (TEP INA219 Current Sensor library V1.0, a
separate library). Demo board: ARDUINO UNO V4.0 (TEP Arduino Library V4.0)
with its built-in serial monitor.